How it works
Molar concentration relates the number of moles of a compound to the volume it's dissolved in. With mass in milligrams, volume in millilitres and molecular weight in g/mol:
- Molarity (mol/L) = mass (mg) ÷ [ molecular weight (g/mol) × volume (ml) ]
- mM = molarity × 1000 · µM = molarity × 1,000,000
- mg/ml = mass (mg) ÷ volume (ml)
Molecular weight is the bridge between mass and moles — a heavier peptide contains fewer moles per milligram, so the same mg/ml gives a lower molar concentration. The MW presets above are approximate reference values; always confirm the exact molecular weight for your specific compound and salt form on its Certificate of Analysis.
10 mg of Retatrutide (MW ≈ 4731) in 2 ml → 10 ÷ (4731 × 2) = 0.001057 mol/L = 1.06 mM = 1057 µM, i.e. 5 mg/ml.
To prepare a stock at a target concentration and then measure aliquots by volume, use the reconstitution calculator. For handling and storage, see the storage guide.
This calculator supports the preparation of laboratory research solutions. Compounds referenced are not for human consumption. MW presets are approximate — verify against your product's Certificate of Analysis.
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